Bermuda Buttercup
“What is this cute little clover like plant?” My volunteer asked while we weeded our community garden. I stood up, looked, and openly groaned. “That is the worst weed on the face of the planet.” I replied. Every gardener and homeowner has seen it hiding in their lawns, creeping between pavers, inhabiting containers, and being a general menace in our gardens and lawns. It is Oxalis or wood sorrel.
Oxalis is a huge genus with 850 different species. All have clover like leaves and contain oxalic acid. Originating in the tropical areas of South America and South Africa, it has spread to every land mass except the polar regions. I was recently fortunate enough to take a cruise of the western Mediterranean during March and I saw Oxalis on every location where we stopped – southern France, Corsica, Malta, Italy, Algeria, Tunisia, Morocco, and Spain. The type of Oxalis I saw tin these locations is called Bermuda buttercup and is about a foot tall with medium sized bright yellow flowers. If it was not so invasive, the flower is pretty, especially if seen growing in large expanses on a hillside.
Oxalis can be found in just about every state in the USA. In California, wood sorrel is known as “demon weed” and is highly invasive. It grows primarily along the Pacific coast and down into Baja, Mexico. The internet is alive with suggestions on how to get rid of this pesky weed. It seems that this genus is able to store nitrogen which enables the plant to thrive even in poor soils.
The most common Oxalis in South Carolina is known as Yellow Woodsorrel. It has green or purplish leaves, is fairly low growing, and has tiny yellow flowers with five petals. I have seen it everywhere from formal gardens to paved parking lots. It can spread by seeds, but unfortunately it has a deep bulb like root. These tiny bulbs can also help the plant spread. You may think you have removed it, but the bulb often remains and the plant grows back.
I used to have oxalis in my lawn in Boston and one day I caught my daughter who was about 10 at the time eating the leaves. She was going through a Ewell Gibbons phase and loved to try eating wild plants. People have eaten Oxalis through the ages and around the world. Native Americans used it as a medicine for mouth sores, cooked it with sugar as a dessert, or ingested it to relieve digestive issues. The bulbs of one variety are sold in New Zealand as a yam. In parts of India, the leaves are added to curries. As the name implies, Oxalis does contain oxalic acid so too much is not a good thing. I had to stop my daughter and tell her to go back to wild asparagus and cattail sprouts.
Not all Oxalis are considered weeds. There is a cultivated variety that is sold in garden centers. It has large shamrock-like purple or bright green leaves and white flowers. If you like it, keep it in a container. When the plant “escapes” it is very difficult to eradicate. Someone planted it in our community pollinator garden and it has spread to places where it is an unwelcome pest.
If you do have Oxalis in your garden, unfortunately, the best way to remove it is by hand. You have to dig deep enough to get those tiny bulbs. There are very fine roots on the top of the soil that are extremely easy to pull out and you think that you have it all. Not so. As I have learned, you will need a good two-pronged weeder to dig those roots out all the way. Weed killers do not penetrate enough to kill all of the roots so you will end up spraying at least three times. I do not like to use herbicides so I am stuck with a deep dig into the soil. And Oxalis likes to hide under plants and along the edges of flowerpots. I always thought that chamber bitter was the worst weed, but for all year annoyance, I cast my vote for Oxalis – it certainly is a weed that has conquered the world.
